default argument for template parameter for class enclosing

code:

template <typename element_type, typename container_type = std::deque<element_type> >
class stack
{
    public:
        stack() {}
        template <typename CT>
        stack(CT temp) : container(temp.begin(), temp.end()) {}
        bool empty();
   private:
       container_type container;
};

template <typename element_type, typename container_type = std::deque<element_type> >
bool stack<element_type, container_type>::empty()
{
    return container.empty();
}

When I compile it gives the error.

default argument for template parameter for class enclosing 'bool stack<element_type,container_type>::empty()'

Why is the compiler complaining and how can I make it work?